Hearing Loss in Adults With Diabetes and Prediabetes: A Systematic Review and Meta-Analysis

Abstract

Diabetes impairs hearing through microvascular damage and neuropathy, yet the prevalence of moderate-to-severe hearing loss (≥ 40 dB HL) remains inadequately explored. Variations by age, diabetes duration, and socioeconomic factors are inadequately characterised. This systematic review quantified the prevalence and comparative risk of moderate-to-severe hearing loss in diabetes and prediabetes, exploring variations across age, national income level, and disease duration. We searched PubMed, Scopus, Web of Science, SPORTDiscus, and CINAHL (2000–2025) for observational studies reporting audiometric thresholds in diabetic or prediabetic subjects (PROSPERO: CRD42018100742). Quality was assessed using the Newcastle–Ottawa Scale. Random-effects meta-analyses generated pooled prevalence and odds ratios (ORs) with 95% confidence intervals (CIs). Publication bias was evaluated via funnel plots and Egger’s regression. Of 3490 records, 29 studies qualified. Most examined type 2 diabetes; one included prediabetes. Twenty-three studies (n = 5221) yielded a pooled prevalence of 24% (95% CI: 19%–30%; I2 = 94%). Eleven studies showed diabetes doubled hearing loss odds versus controls (OR = 2.41, 95% CI: 1.62–3.60; I2 = 86.6%). Risk was significantly elevated in younger adults (< 60 years: OR = 3.03, 95% CI: 2.17–4.22) but not in older adults (≥ 60 years: OR = 1.52, 95% CI: 0.72–3.22). Low- and middle-income countries showed the highest risk (OR = 4.51, 95% CI: 2.43–8.40) versus high-income countries (OR = 1.78, 95% CI: 1.05–3.02). Diabetes duration < 10 years conferred elevated risk (OR = 2.68). Small-study effects were detected (Egger’s p = 0.019) but sensitivity analyses confirmed robustness. One in four diabetic adults has clinically significant hearing loss, particularly in younger individuals and resource-limited populations. These findings support the integration of routine audiometric screening into diabetes care.